TurquoiseChevrotain which bit did you read?
I would not say that Babycentre was the diffinative authority but at
www.babycenter.com/0_raising-boys-and-girls-differences-in-development_3659011.bc
Was it the first bit:
"Between the big growth stages of infancy and adolescence, boys and girls grow in height and weight at about the same slow but steady rate."
If you read on "There aren't notable differences between the sexes until late elementary school – that's when girls start to grow taller faster, although boys catch up and exceed them within a few years."
Boys gross motor skills develop slightly faster, girls fine motor skills grow fast, this could be training as boys may be given a ball and girls a pencil first, but I think most parents would universally give a ball before a pencil irrespective of sex.
"Boys are also more physically aggressive and impulsive, as revealed by studies of their brains. The pleasure center of the brain actually lights up more for boys when they take risks. That's not to say that girls aren't active risk-takers, only that, on average, boys are more so."
Again this could be training.
It then goes on to point out the type of home you are born in may influence things.
"Researchers say it's possible that sex-related genes or hormones account for the different ways the brains of boys and girls react to human speech." More boys are late talkers etc. Although again this could be accounted for by the way children are socialized.
"Girls tend to be better at reading nonverbal signs, like tone of voice and expression, which also makes them better communicators early on because they can connect feelings and words faster." Again is this training or a natural ability? I don't know.
Again not sure of the reason... "On average, girls are potty trained earlier than boys, though it's unclear whether this is due to physical or social differences."
"Girls enter puberty about one year before boys."
"Researchers continue to study the developmental differences between boys and girls and what causes them, but it's important to remember that biology alone doesn't determine the kind of son or daughter you'll have. Exposing your child to a wide range of activities and experiences is the best way to support a well-rounded, active child."
So it's not clear why there are differences but it seems there are. None of these differences mean girls are better or worse than boys or more of less likely to succeed etc. If we were not always required to prove that girls were just as good as boys maybe we would be interested in these differences. Of course the brain is very plastic so we may never know if these things are all just learnt.